1、 TIA/EIA-334-C-2000 APPROVED: APRIL 27, 2000 REAFFIRMED: SEPTEMBER 14, 2005 REAFFIRMED: JULY 29, 2014 TIA-334-C (Revision of TIA/EIA -334-B) May 2000Signal Quality at Interface Between Data Terminal Equipment and Synchronous Data Circuit- Terminating Equipment for Serial Data Transmission NOTICE TIA
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20、OULD NOT BE PUBLISHED BY TIA WITHOUT SUCH LIMITATIONS. TIA-334-CiSIGNAL QUALITY AT INTERFACE BETWEENDATA TERMINAL EQUIPMENTAND SYNCHRONOUS DATA CIRCUIT-TERMINATING EQUIPMENTFOR SERIAL DATA TRANSMISSIONCONTENTS1 SCOPE. 12 NORMATIVE REFERENCES 13 DEFINITIONS. 23.1 Co-directional Timing. 23.2 Contra-di
21、rectional Timing. 23.3 Duty Cycle 33.4 Jitter 33.5 Signal Element. 33.6 Signal Element Timing. 33.7 Transition 33.8 Unit Interval 34 INTERFACE CONFIGURATIONS. 34.1 Point of Demarcation . 34.2 Interconnecting Cable 45 INTERFACE AT TRANSMITTING TERMINAL . 45.1 Timing Signals 55.1.1 Frequency Accuracy.
22、 55.1.2 Duty cycle of Timing Signals 55.1.3 Jitter on circuit DB, Transmit Signal Element Timing (DCE Source) 55.1.4 Jitter on Circuit DA, Transmit Signal Element Timing (DTE Source) 55.2 Timing Relationship Between Transmit Data and Transmit SignalElement Timing 55.2.1 Contra-directional Timing (DC
23、E Source Timing) . 55.2.2 Co-directional Timing (DTE Source Timing) 56 INTERFACE AT RECEIVING TERMINAL. 7TIA-334-Cii6.1 Timing Signals 76.1.1 Frequency Accuracy. 76.1.2 Duty Cycle of Timing Signals 76.1.3 Jitter on Circuit DD, Receiver Signal Element Timing 76.2 Timing Relationship between Received
24、Data and Receiver SignalElement Timing 76.2.1 Timing Signals Provided by DCE (Co-directional Timing). 77 MEASUREMENT OF SIGNAL QUALITY 87.1 Signal Quality for Unbalance Generators 97.1.1 Interchange Circuit Signal Return. 97.1.2 Generator Voltage. 97.1.3 Signal Quality Voltage Thresholds . 97.1.4 St
25、andard Test Load 107.2 Signal Quality for Balance Generators 107.2.1 Generator Voltage. 107.2.2 Signal Quality Threshold Voltages . 117.2.3 Standard Test Load 11ANNEX A (INFORMATIVE) 12A INFORMATIVE REFERENCE. 12TIA-334-CiiiFOREWORD(This foreword is not part of this Standard)This Standard was formul
26、ated under the cognizance of TIA Subcommittee TR-30.2 on DataTransmission Interfaces and Protocols.This Standard is a revision to EIA-334-B. This revision adds requirements for: TIA/EIA-687,Medium Speed Interface for Data Terminal Equipment and Data Circuit TerminatingEquipment along with its associ
27、ated electrical characteristics standard TIA/EIA-423-B,Electrical Characteristics of Unbalanced Voltage Digital Interface Circuits; and TIA/EIA-723,High Speed 232 Type DTE/DCE Interface along with its associated electrical characteristicsstandard TIA/EIA-694, Electrical Characteristics for an Unbala
28、nced Digital Interface for DataSignaling Rates Up to 512 kbit/s. It also incorporates new timing diagrams for Figures 4 - 8which better represent the requirements set forth in this standard.Annex A is informative and is not considered part of this standard.TIA-334-CivThis Page Intentionally Left Bla
29、nkTIA-334-C11 SCOPE1.1 This Standard is applicable to the exchange of serial binary data signals and timingsignals across the interface between Data Terminal Equipment (DTE) and synchronousData Circuit-terminating Equipment (DCE). The DCE is considered to be synchronous if thetiming signal circuits
30、are required at the transmitting terminal or the receiving terminal, orboth. The signal quality requirement is limited to synchronous transmission at the interfacewith synchronous DCEs. Signal quality pertaining to asynchronous DTEs is not part of thisStandard.1.2 The interfaces referred to in this
31、Standard conform to TIA/EIA standards:TIA/EIA-232-FTIA/EIA-530-A together with TIA/EIA-422-B electrical characteristicsTIA/EIA-687 together with TIA/EIA-423-B electrical characteristicsTIA/EIA-723 together with TIA/EIA-694 electrical characteristics1.3 This Standard specifies signal quality in relat
32、ion to jitter, duty cycle, and frequencyaccuracy of timing signals and time displacement between data signals and timing signals.Electrical specifications for the signals are not part of this Standard but are part of thereference interface specifications.1.4 This Standard is of particular importance
33、 when the equipments in a system arefurnished by different organizations. It does not attempt to indicate what action, if any, is tobe taken if the limits are not met, but it is intended to provide a basis for agreement betweenthe parties involved.1.5 This Standard does not describe any requirements
34、 for error performance for eithera complete system or any system components. It should not be assumed that compliancewith this Standard will produce error rates that are acceptable in any particular application.1.6 Any equipment which is represented as complying with this Standard shall meetthe appl
35、icable specifications within the range of those factors which are described asappropriate for the normal operation of the equipment, such as primary power voltage andfrequency, ambient temperature, or humidity.1.7 This Standard may also be used for DTE to DTE direct connections.2 NORMATIVE REFERENCE
36、SThe following standards contain provisions which, through reference in this text, constituteprovisions of this Standard. At the time of publication, the editions indicated were valid. AllStandards are subject to revision, and parties to agreements based on this Standard areencouraged to investigate
37、 the possibility of applying the most recent editions of thestandards indicated below. ANSI and TIA maintain registers of currently valid nationalstandards published by them.TIA-334-C2ANSI/TIA/EIA-232-F-1997, Interface Between Data Terminal Equipment and Data Circuit-Terminating Equipment Employing
38、Serial Binary Data Interchange.ANSI/TIA/EIA-422-B-1995, Electrical Characteristics of Balanced Voltage Digital InterfaceCircuits.ANSI/TIA/EIA-423-B-1995, Electrical Characteristics of Unbalanced Voltage Digital InterfaceCircuitsANSI/EIA/TIA-530-A-1998, High Speed 25-Position Interface For Data Termi
39、nal Equipmentand Data Circuit-Terminating Equipment Including Alternative 26-Position Connector.ANSI/TIA/EIA-687-1997, Medium Speed Interface for Data Terminal Equipment and DataCircuit Terminating EquipmentANSI/TIA/EIA-694-1997, Electrical Characteristics for an Unbalanced Digital Interface forData
40、 Signaling Rates Up to 512 kbit/sANSI/TIA/EIA-723-1998, High Speed 232 Type DTE/DCE Interface3 DEFINITIONSFor the purposes of this Standard, the following definitions apply:3.1 Co-directional TimingA configuration in which a timing signal and associated binary signals (data or control) aretransferre
41、d in the same direction across the interface (see Figure 1).Figure 1 - Co-directional Timing3.2 Contra-directional TimingA configuration in which a timing signal and associated binary signals (data or control) aretransferred in opposite directions across the interface (see Figure 2). This configurat
42、ionwould apply to Transmit Clock/Data only.DataTerminalEquipmentDataCircuitTerminatingEquipmentInformation signaltiming signalTIA-334-C3Figure 2 - Contra-directional Timing3.3 Duty CycleIn signal element timing the duration of the signal condition from which a significanttransition is originated. Th
43、e duration is usually expressed as a percentage of the unitinterval.3.4 JitterThe degree of short term variation of the significant instant of a digital signal from its idealposition in time.3.5 Signal ElementEach of the parts constituting a data signal and distinguished from the others by its natur
44、e,magnitude, duration and relative position (or by one or some of these features only).3.6 Signal Element TimingA signal used to determine the duration of signal elements and to achieve synchronizationwith a synchronous transmission system.3.7 TransitionA change from one significant condition to ano
45、ther in a data signal.3.8 Unit IntervalThe duration of the shortest nominal signal element. It is the longest interval of time suchthat the nominal durations of the signal elements in a synchronous system are wholemultiples of this interval.4 INTERFACE CONFIGURATIONS4.1 Point of DemarcationDataTermi
46、nalEquipmentDataCircuitTerminatingEquipmentInformation signaltiming signalTIA-334-C4Figure 3 illustrates the point of demarcation between the DTE and the DCE. The connector,which is the point of demarcation, shall be physically attached to the DCE or extended bymeans of a cable (less than 3 meters o
47、r 10 feet).The measurements of relative phase relationship (timing displacement) between data andtiming signals, jitter, duty cycle, and frequency accuracy of the timing signals shall be madeat the point of demarcation.Table 1 specifies the mnemonic terms used for timing and data signals relating to
48、 thisstandard and the direction of the DTE-DCE interchange circuits.Table 1 - Interchange CircuitsTimingCircuit Name MnemonicCo ContraTimingSourceITU-T V.24NumberTransmit Signal ElementTimingDB X DCE 114Transmit Signal ElementTimingDA X DTE 113Receiver Signal ElementTimingDD X DCE 115Transmitted Dat
49、a BA DTE 103Received Data BB DCE 104Figure 3 - Point of Demarcation4.2 Interconnecting CableThe length of the interconnecting cable is not specified. Guidelines on the maximum cablelength are included in the applicable interface standards. In the case of contra-directionaltiming, the requirements on timing displacement at the higher data rates (greater than 20kbit/s) may be more restrictive than the guidelines presented in the interface standards.5 INTERFACE AT TRANSMITTING TERMINALThe interchange circuits associated with the transmit direction of synchronous DTEs shouldoperate within the
